Optical modules are used for transmitting optical signals over fibers in optical fiber networks. Common types of optical modules include transmitter modules, receiver modules, transceiver modules and transponder modules. Optical transceivers transform optical signals to electrical signals or electrical signals to optical signals. Optical transceivers may comprise photoelectrical devices, functional circuits, optical interfaces, etc., which play important roles in fiber optical communication systems. Depending on the design of the optical module housing, transceivers may be small form pluggable (SFP), gigabit interface converter (GBIC), protocol independent small form factor pluggable (XFP), etc. SFP optical transceivers, which function similarly to GBIC modules, are half the size of GBIC modules and may have more than twice the number of interfaces as GBIC modules. Many optical modules, including SFP optical transceivers, are “hot-pluggable” devices, in that they allow the user to insert and remove the module without significant interruption to the operation of the system. Such pluggable modules install into sockets or cages and may be locked into, and unlocked from the sockets or cages utilizing one of a variety of types of latch/release mechanisms.
The dimensions, arrangements, communications ports (e.g., input and/or output pins) and/or footprints of the optical modules and their housings are typically defined both by industry standards and a Multi-Source Agreement (“MSA”) among manufacturers of such modules. The MSA specifies the mechanical dimensions and opto-electrical characteristics of the module and its housing, but allows for variations in module and housing design. The differences in design may lead to differences in the deployment and installation of the module. Most notably, the latch/release mechanisms may vary from manufacturer to manufacturer. Some conventional mechanisms comprise a tapered end or projection that may be deployed or retracted through a lock hole or slot in the module housing. When a module housing is inserted into a socket, the tapered end or projection is deployed such that it protrudes through the lock hole or slot in the casing or the module housing and engages the socket to latch or lock the module in place. To remove the module housing from the socket, the tapered end or projection is retracted into the lock hole or slot to unlatch or unlock the module housing and disengage it from the socket.
Optical modules and housings with conventional latch/release mechanisms can also include Mylar tab latches, actuator button latches and bale-clasp latches. Conventional latch/release mechanisms are configured to work on a lever principal. Specifically, the tapered end or projection is on one end of the lever, and the other end of the lever is connected to the tab, actuator button or bale-clasp. When releasing or unlocking the module, the tapered end or projection is disengaged from the socket by lifting the tab, the actuator or the bale-clasp to move the tapered end or projection down and into the module housing. The module housing may then be removed from the socket by applying a force along the module housing thereby pulling the module housing out of the socket. However, removing the module housing when the lever is not in the proper position can damage the tapered end or projection and/or the socket or cage.
FIGS. 1-2 show a conventional module housing 100 with a bale-clasp latch. Referring initially to FIG. 1, the module housing 100 includes a module base or chassis 109, a bale or handle 113, and a single piece latch/slider 105 with a projection 104 that locks the module housing 100 into a corresponding socket (not shown). In FIG. 1, the bale 113 is shown in the lowered position and the latch/slider 105 in the locked position. When the bale 113 is moved from a lowered position to a raised position, the latch/slider 105 and the projection 104 move down into the chassis 109 (the “unlocked” position). When the bale 113 is moved from a raised position to a lowered position, the latch/slider 105 and the projection 104 move up and out of the chassis 109 (the “locked” position). As shown in FIG. 1, the bale 113 is attached to the chassis 109 by shafts or pins 150.
FIG. 2 shows the exemplary module housing 100 of FIG. 1 with the bale 113 in a raised position, and the latch/slider 105 and the first projection 104 in the unlocked position. In the raised position, the bale 113 is at an angle of 90 degrees from the lowered position, and the far end of the latch/slider 105 is lowered such that the first projection 104 is flush with or below the surface of the chassis 109. As sown in FIG. 2, the bale 113 is attached to the latch/slider by slider pins 156.
To operate the conventional release mechanisms described above, a force must first be applied to the latch/slider to lock or unlock the module housing and then a second force must be applied parallel to the module housing to insert or remove the module housing from the socket. If the force applied first does not completely lock or unlock the module housing prior to the second force being applied, the latch, the projection and/or the socket may be damaged. Consequently, conventional latches may be difficult to properly seat, lock in place and/or remove.
For example, when inserting a module with a conventional latch into a socket, in order to verify that the module is properly seated, it is generally recommended that the user verifies both audibly and visually that the module is locked into position. Visual-only inspection can produce intermittent and/or total loss of functionality and/or conductivity because vibrations, connecting cable movement and/or temperature changes may result in unseating of the module if it is not fully locked into position. Likewise, audible-only verification may result in faulty seating because some modules will emit an audible “click” once seated, while others will click upon actuation of the latching mechanism, but will still require additional force to properly seat the housing. In fact, because of the shortcomings of the methods of verifying that the module is securely locked into place, one should mechanically verify that the module is locked into place after communication cables, wires or fibers are installed. Mechanical verification is performed by applying an outward force to the cable, wire or fiber. If the module is not properly seated and locked, the module will come out of the socket.
Generally, and regardless of type of conventional latch, mechanical verification is a relatively time-consuming and cumbersome process, particularly when many modules require installation in a short period of time. Therefore, mechanical verification is a step that may often be skipped by users when inserting such modules. Consequently, modules may be improperly installed, may have only intermittent functionality, or may lose functionality entirely, causing interruption and/or failure of the device in which such modules are installed. Additionally, removal of optical modules from the corresponding sockets may be difficult without causing damage to the latch and/or the module. For example, to remove a module having a Mylar tab latch from a socket, the user gently pulls the tab in a slightly downward direction until the module disengages from the socket. If the Mylar tab is pulled too vigorously and/or twisted, the tab can detach from the module thereby causing failure of the mechanism. If the latch/slider is not in the proper position when the module is removed, the tapered end or projection and/or the socket may be damaged.
Chinese Patent Application No. 201010153763.1 discloses a device capable of releasing a SFP optical transceiver by applying a force to rotate a bale or handle and then applying a second force along the optical transceiver to remove the transceiver from the socket. A locking plate on the top of the casing or housing of an optical transceiver, and a lock hole or slot in the locking plate, are operated by an arc unlocking unit with an arc-shaped unlocking sliding piece and unlocking spring pieces, which are configured to lift the lock plate up and release the tapered end or projection from the lock hole. Specifically, when the bale or handle rotates, the arc unlocking unit lifts the locking plate end to the height of the tapered end or projection, thereby releasing the optical transceiver from the socket. The optical transceiver may then be removed from the socket by applying a second force along the optical receiver. However, this release mechanism requires bending of the locking plate and/or the slider to unlock the optical transceiver, thus requiring a relatively high releasing force. Such operation is inconvenient and places repeated high bending stress on the locking plate and/or the slider. Other conventional module latches may have similar disadvantages when removing a module from a socket.
Therefore, a need exists for a module housing that is easily seated, securely locked into position, and inserted and removed with minimal force and/or damage to the latch, module or socket.
This “Discussion of the Background” section is provided for background information only. The statements in this “Discussion of the Background” are not an admission that the subject matter disclosed in this “Discussion of the Background” section constitutes prior art to the present disclosure, and no part of this “Discussion of the Background” section may be used as an admission that any part of this application, including this “Discussion of the Background” section, constitutes prior art to the present disclosure.